x2 it is possible. it has been done.It's been done before, but you'd most likely end up spending less on the B20. To answer your question though, they make mounts for the motor and the H2B kit, which allows you to use your B-series trans. with an H-series engine. And you'd still have to figure out wiring.
Mounts: http://www.innovativemounts.com/ProductDetails.asp?ProductCode=29354
H2B kit: http://www.jhpusa.com/store/pc/viewPrd.asp?idproduct=4303
Look around, you can probably find them cheaper. That's just to give you an idea.